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Arctic climate: USGS scientists document walrus response to shrinking summer sea ice cover

A Walrus in the Chukchi Sea during a tagging survey onboard the Norseman II in June 2010. Photo courtesy Sarah Sonsthagen , U.S. Geological Survey.

New study a first step in understanding long-term impacts to walrus populations

By Summit Voice

SUMMIT COUNTY — Scientists with the U.S. Geological Survey say walruses in the Arctic are responding to shrinking summer sea ice by arriving earlier at their northern feeding grounds on the broad continental shelf of the Chukchi Sea.

When the sea ice over the continental shelf melts completely in the fall, they “hauled out” onshore in large aggregations and foraged for food closer to shore. Hauling out refers to the behavior associated with seals and walruses of temporarily leaving the water for sites on land or ice, according to the study published in the journal Marine Ecology.

The researchers said they’re not exactly sure how this may affect walrus populations in the long run, however it is known that immature walruses are more susceptible to mortality from trampling onshore, Additionally, hauling out onshore and using nearshore feeding areas may require more energy. Continue reading

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Arctic sea ice melts at nearly double the average rate in August, dips below 4 million square kilometers

The graph above shows Arctic sea ice extent as of September 3, 2012, along with daily ice extent data for the previous five years. 2012 is shown in blue, 2011 in orange, 2010 in pink, 2009 in navy, 2008 in purple, and 2007 in green. The 1979 to 2000 average is in dark gray. The gray area around this average line shows the two standard deviation range of the data. Sea Ice Index data. Graphic courtesy NSIDC.

August extent just half of the average levels recorded in the 1980s and 1990s

By Summit Voice

SUMMIT VOICE — For the first time in the modern satellite record, Arctic sea ice extent has dropped below 4 million square kilometers, marking a 45 percent reduction from the levels recorded in the 1980s and 1990s.

The National Snow and Ice Data Center said the ice extent may shrink for another week or so before the Arctic region starts to cool off, leading to a renewed cycle of freezing.

During most of August, the ice extent remained well below the levels of 2007, when the previous record low was set. The only place where sea ice remained near its average long-term extent was along the east coast of Greenland. Continue reading

Climate: May Arctic sea ice extent dips below average

Arctic sea ice extent dipped down toward historic low levels by the end of May. GRAPH COURTESY NATIONAL SNOW AND ICE DATA CENTER.

Average May sea ice extent has been declining by 2.3 percent per decade

By Summit Voice

SUMMIT COUNTY — After hovering near average in April, Arctic sea ice melted rapidly in early May, dipping to near the extent seen in 2007, when the year ended with a record low sea ice extent.

But in the monthly update, scientists at the National Snow and Ice Data Center said there is little historic correlation between May levels and the extent at the end of the melt season in September.

For the month, Arctic sea ice extent averaged 5.07 million square miles, which is about 185,000 square miles below the 1979 to 2000 average. Record low sea ice extent during the satellite measurement era was in 2004. Continue reading

February Arctic sea ice extent below average

Despite rapid monthly growth, Arctic ice extent continues long-term decline

Arctic sea ice grew at an above-average pace in February, 2012.

Monthly February ice extent for 1979 to 2012 shows a decline of 3 percen per decade. GRAPHIC COURTESY NSIDC.

By Summit Voice

SUMMIT COUNTY — Arctic sea ice extent grew at a faster than average rate, and spiked in late February, but despite spreading farther than normal on the Pacific side of the Arctic, the overall extent was lower than average. Thick multi-year ice continues to melt quickly, according to NASA researchers.

Overall, the Arctic gained 369,000 square miles of ice during the month. This was 188,000 square miles more than the average ice growth for February 1979 to 2000.

For the month, the ice extent averaged 5.62 million square miles, about 409,000 square miles below the 1979 to 2000 average extent, making it the fifth-lowest February ice extent in the satellite data record, according to the monthly update from the National Snow and Ice Data Center. Continue reading

Arctic sea ice below average in December

Arctic sea ice extended trended below average during much of December.

December ice declining at a rate of 3.5 percent per decade

By Summit Voice

SUMMIT COUNTY — Arctic sea ice extent remained unusually low in December, despite a positive phase in the Arctic Oscillation. At the end of the month, the extent was the third-lowest in the satellite record. Five of the lowest December readings have been in the past six years, reflecting the steady shrinkage of Arctic, now declining at a linear rate of 3.5 percent per decade.

The lowest sea ice was on the Atlantic side of the Arctic in the Barents and Kara seas, according to the Jan. 5 update from the National Snow & Ice Data Center. Continue reading

Climate: Arctic sea ice lingers below average

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November ice extent the third-lowest on record

By Summit Voice

Arctic sea ice cover grew at an average pace through November, but after starting at near-record low levels, the extent remained far below average, according to the monthly report from the National Snow and Ice Data Center.

Overall, the Arctic gained 2.36 million square kilometers (911,000 square miles) of ice during the month, slightly more than the average November ice gain.  At the end of the month, sea ice covered 4.19 million square miles, the third-lowest in the satellite record for the month, behind 2006 and 2010. Continue reading

Climate: Arctic sea-ice extent lags below average

Despite rapid October growth, ice remains near record-low levels

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By Summit Voice

SUMMIT COUNTY — Arctic sea ice grew about 40 percent faster than average in October, but after an extensive summer melt-off, large areas of open water remained in the Beaufort and Chukchi seas, leading to unusually warm conditions along parts of the Siberian coast.

At the end of October, the ice extent was the second-lowest in the era of satellite records, trailing only the record low year of 2007. During that span, average October sea ice extent has declined about 6.6 percent each year, according to the National Snow and Ice Data Center.

Arctic sea ice extent is on a long-term downward trend.

Continue reading

Climate: Arctic sea ice shrinks to 2d-lowest extent on record

Arctic sea ice receded to the second-lowest extent on record this year. MAP COURTESY NATIONAL SNOW AND ICE DATA CENTER.

Researchers say shrinking ice is well outside the range of natural climate variability

By Summit Voice

SUMMIT COUNTY — Scientists measuring the blanket of sea ice that floats on the Arctic Ocean say this year’s melt has ended, with the extent of the ice reaching its second-lowest level on record, dating back to 1979.

This year’s minimum of 1.67 million square miles is more than 1 million square miles below the 1979-2000 monthly average extent for September — an area larger than Texas and California combined.

The last five years have been the five lowest Arctic sea ice extents recorded since satellite measurements began in 1979, said CU-Boulder’s Walt Meier, an NSIDC scientist.

“The primary driver of these low sea ice conditions is rising temperatures in the Arctic, and we definitely are heading in the direction of ice-free summers,” Meier said. “Our best estimates now indicate that may occur by about 2030 or 2040.” Continue reading

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